Moderate hemodilution technic in surgical procedures. Blood electrolyte balance in patients undergoing operation for gastric and duodenal ulcer.

Studies to determine selected blood electrolyte concentrations showed no disturbances in serum sodium, chloride, and copper concentrations during and after moderate hemodilution to 30 per cent of hematocrit. Sudden significant decreases in serum potassium, magnesium, and total calcium concentrations at ten minutes after hemodilution were the result of physical dilution only and did not have negative effects on organs, especially the heart. We observed a significant decrease in serum iron concentration with a gradual return to the control value; we cannot explain this phenomenon because it resulted neither from dilution nor blood loss. Our results require that caution be exercised and that the dilution fluid employed be changed when more significant hemodilution (below 30 per cent of hematocrit) is intended, so that suspected, more intensive sudden alterations in electrolyte concentration are prevented.